But multiple sources say that Spotify will NOT have an exclusive lock on
Facebook's music offering, which will be announced soon.

Last week at an event in San Francisco, Rdio CEO Drew Larner was
asked directly whether that subscription service would appear in
the Facebook offering. He simply smiled and
said he couldn't comment on the company's relationship with
Facebook -- as close to a non-denial
denial as you can get.

This morning, a Rhapsody spokesperson was even more explicit:
"We have plans for deep Facebook integration with the next release of
our product, and I can say on good authority that there will be
more music content in Facebook than Spotify."

Spotify might get there first, but if it
gets an exclusive it won't last long. So it's hard to see how
Facebook will help Spotify get to 50 million users unless it has
some other huge advantage over these other subscription services
-- 10 hours of free content per month, like it offers in Europe,
would be a nice start.